1. Field of the Invention
The present disclosure relates to a liquid crystal display device, more particularly, to a liquid crystal device that is able to improve a liquid crystal response time by applying overdriving especially to a high gradation region and an video processing method of the liquid crystal device.
2. Discussion of the Related Art
Liquid crystal display devices display images by using electrical or optical characteristics of liquid crystal. Specifically, such a liquid crystal display (LCD) device includes a liquid crystal panel for displaying images via a pixel matrix and a driving circuit for driving the liquid crystal panel. The LCD device includes a backlight unit, because the liquid crystal panel of the LCD device is a non-luminescent device. Liquid crystal alignment of each sub-pixel provided in the liquid crystal panel is variable according to a video signal to adjust transmissivity of lights emitted from the backlight unit such that the image may be displayed. Such the LCD devices have been used in compact display devices such as mobile communication terminals, portable computers and liquid crystal televisions and large-sized display devices more and more broadly.
The LCD device can be used to display motion pictures, because it is an active matrix type having a thin film transistor as switching device for each sub-pixel. However, the LCD device has a slow response time caused by unique characteristics such as viscosity and elasticity, and a hold type driving. Because of that, the LCD device would have a problem of motion blur generated by an afterimage of a previous frame. To solve this problem, an overdriving control (hereinafter, ODC) is used in that an overshoot voltage over a goal value is applied when there is change of data, after comparing data of neighboring frames to each other, to improve the liquid crystal response time in proportion to the applied voltage.
However, according to the ODC method of the related art, a range of gamma voltages for input data is identical to a range of gamma voltages for ODC data. As a result, it is impossible to apply ODC to high and low gradation regions. For example, it is impossible to increase voltages of white gradation data (255) out of the input data and to apply ODC to the white gradation data. Because of that, the liquid crystal response time in bright image of a motion picture and it is limited to improve motion blur.